I have a friend of mine that tried to convince me that I would abandon MS services for Google. I use as little Google service as I can on my Note 8. Having been a Windows user for years, everything I've used and stored uses MS services. I'm not hating on Google, I just don't see a need to switch from MS to Google, simply because I am now using an Android phone. Outlook ties in all my emails, to include Google and Yahoo. I use Office regularly, OneDrive has been my cloud storage source for years and Groove plays all the music I have stored on OneDrive. No to mention, documents and pictures. The only thing I'm missing right now is Movies and TV app from MS. I've learned to live without the Live tiles, but I do miss them. I have Launcher 10, but I use MS Launcher now. Launcher 10 is great for anyone still wanting to have the look and feel of Live Tiles. It even has some features I would have loved to see on Windows 10 Mobile.
My point with all this is, iOS or Android will depend on a few factors.
1. What services do you need?
2. Are you invested in a particular ecosystem?
3. If so, how easy is it to switch over to another ecosystem and use proprietary services or services already used?
4. Do you want flexible customization or limited?
5. Do you want hardware variety or does it matter?
There are other factors, but primarily focused on ecosystem and services to decide that would ultimately determine which to choose.